textproduct: Albany

WHAT HAS CHANGED

Threat for severe weather increased for Thursday. SPC now has a Slight Risk (Level 2 of 5) for parts of the area for Thursday.

KEY MESSAGES

1) Scattered thunderstorms are expected to develop Thursday afternoon and evening across all of eastern New York and western New England. A few storms could be severe with the potential for damaging winds along with heavy downpours, which could result in isolated flash flooding.

2) Although a few additional showers or thunderstorms are possible on Friday, dry weather is expected for the weekend with seasonable temperatures.

DISCUSSION

KEY MESSAGE 1...

An upper level disturbance will be passing by to the north across southern Canada on Thursday. At the surface, a weak surface trough is expected to pass through the area from west to east. With a low-level southerly flow in place, it will be noticeably more humid than recent days, with dewpoints reaching the mid to upper 60s. Once a warm front passes through the area early in the day, instability will be increasing. 00z HRRR shows SBCAPE values will reach 1000-2000 J/kg and the 00z SPC HREF also shows mean values exceeding 1000 J/kg in valley areas as well. With the disturbance passing by to the north, there should be some shear in place as well, with 0-6 km bulk shear exceeding 30 kts.

Although the day will start out dry, scattered showers and thunderstorms are expected to develop during the afternoon hours and continue into the evening. With enough instability and shear in place, some of the storms may become severe, with the main threat being damaging winds. There could be enough helicity for an isolated tornado, but damaging straight-line winds looks to be the most likely threat. CAMs suggest that storms may organize into short lines or bow echoes, especially by the evening hours. Storms may linger into the late-evening, but should dissipate towards midnight, as the surface trough pushes eastward and the loss of daytime heating reduces the available instability. SPC has a Slight Risk (level 2 of 5) for parts of the area (Mohawk Valley and eastern Catskills), with a marginal risk (level 1 of 5) for the remainder of the area.

In addition, there will be the threat for heavy downpours and isolated flash flooding, thanks to the high moisture in place (PWATS reaching 1.50 to 2.00", which is about 1-2 STD above normal). This allow for high intensity rainfall rates within any thunderstorm. Urban and poor drainage areas will be most as risk, as well as locations that see multiple thunderstorms.

KEY MESSAGE 2...

The actual cold front will be crossing the region during the day on Friday. A few additional showers or thunderstorms can't be ruled out on Friday ahead of the front, although the threat for stronger storms looks lower on Friday due to less instability and shear, and the front passing earlier in the day.

Behind the front, it will turn less humid for the weekend, especially on Saturday when dewpoints will mainly be in the 50s. With high pressure in control, there should be plenty of sun both days with no threat for precipitation. Temperatures will be fairly seasonable, with daytime temperatures reaching the upper 70s to low 80s and overnight lows in the 50s, with even some 40s across the high terrain.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Through 12Z Thursday... Light and variable winds persist across the region this morning, with some lingering mist/fog and lower cigs at KGFL and KPSF. This should burn off quickly this morning, returning all terminals to VFR by mid-morning. With high pressure dominating over the area today, cigs are expected to gradually scatter out and rise throughout this morning and afternoon. A trough will begin to build into the region tonight, bringing light southerly winds to KALB and KPSF, while KGFL and KPOU are expected to see calm winds during that time. There is potential for the development of mist/fog tomorrow morning at KGFL and KPOU, which could bring brief reductions in cigs and vis in the last several hours of the TAF period. At this time, only KGFL is expected to see reductions to IFR but confidence will increase with future TAF cycles.

Outlook...

Thursday Night: High Operational Impact. Likely SHRA...TSRA. Friday: Low Operational Impact. NO SIG WX. Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: Low Operational Impact. Slight Chance of SHRA...TSRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.